Shear retrofitting with manually made NSM FRP sheets (MMFRP) of RC beams

Abstract

This paper presents an experimental study to evaluate the effectiveness of the proposed carbon manually made fibre-reinforced polymer (MMFRP) folded sheet for shear strengthening of nine RC beams using near-surface mounted (NSM) method, in addition to an unstrengthened control beam. In the laboratory, MMFRP folded sheets were manually manufactured. MMFRP is made by folding an FRP sheet into appropriate groove widths. Carbon MMFRP folded sheets with varying strip amounts, FRP areas and development lengths increase the shear strength of rectangular-reinforced concrete (RC) beams. Double, triple and quadruple strips of FRP were intended to test the enhancement of strength capacity when the strip quantity was just increased without modifying the FRP area and development length. In addition, different FRP areas and development lengths were used to analyse the FRP area and development length of NSM-FRP strips. The advantages of beam strengthening employing different MMFRP folded sheets are explored based on experimental findings. In comparison with the control beam, beams with double, triple and quadruple strips demonstrate 68%, 59% and 74% improvements in shear load-carrying capacity, respectively. However, the study discovered that if the number of strips, FRP area or development length is raised, the member’s shear strength capability is estimated to improve.